re:
!> We want to determine in our application which domain call.

Capture the requesting IP and do a reverse DNS lookup, although that won't help you.

There's many clients which share IPs, via proxies, with many other clients.

Juan T. Llibre, asp.net MVP
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you may want to check Request.ServerVariables["HTTP_X_FORWARDED_FOR"],
and then, if that one's empty,
look in Request.ServerVariables["REMOTE_ADDR"] ....something along
this lines.

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